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What health considerations are there?

Note: It is important to take level of exposure into account when considering health effects of pollutants.

Pollutant

What is it?

Health Effect

Methane

A colorless, odorless, tasteless, and flammable gas that is the primary component of natural gas.

Toxicological data suggests that pure methane is nontoxic. 2 High concentrations can cause oxygen-deficient air spaces, fire hazards, or explosions. 3 Water contaminated with methane poses risk of explosion if ignited. 4

Hydrogen Sulfide

Chemical air hazard produced during petroleum/natural gas drilling and refining. 5 It is a colorless, flammable, and extremely hazardous gas with a strong odor of rotten eggs at low concentrations. Regulations require onsite monitoring for hydrogen sulfide.

Lower levels and long-term exposure can cause eye irritation, headache, and fatigue. 6 Inhalation of very high concentrations can result in respiratory distress, respiratory arrest, or death. 7

Benzene

A volatile organic compound (VOC) found in crude petroleum, natural gas, and diesel exhaust. May be released during well unloadings or other maintenance. 8 It is a colorless to light yellow liquid with an aromatic odor.

Low levels of exposure can result in irritation to skin, eyes, and respiratory systems, dizziness, tremors, and fatigue, among other symptoms; it has also been linked to reproductive effects. 9 Exposure to very high concentrations has been linked to leukemia and can result in death. 10

Xylene

A VOC found in natural gas and hydrocarbons issuing from the well during the fracturing process. It is a colorless liquid with a sweet-smelling odor and is flammable.

Low levels of exposure are not associated with health risks. 11 However, short-term exposure at high levels can cause dizziness, confusion, irritation of skin, eyes, and throat, difficulty breathing, and possible changes in the liver or kidneys. Very high levels can result in unconsciousness or death. 12

Toluene

A VOC found naturally in hydrocarbon deposits, and might be present in chemicals used during the drilling and fracking process. 13 It is a colorless liquid with distinct sweet odor.

Symptoms of low to moderate levels of toluene exposure include fatigue, confusion, memory loss, nausea, loss of appetite, and hearing and vision loss. 14, 15 Inhalation of high levels can cause light-headedness, dizziness, fatigue, unconsciousness, and death; it has also been linked to birth defects and kidney damage. 16

Hexane

A VOC that is highly flammable; vapors can be explosive. 17 It is a colorless liquid with a gasoline-like odor.

Inhalation is most common route of exposure, but it can be found in contaminated private wells. 18 Inhalation of low levels is not associated with health effects. 19 High levels can result in nausea, eye and nose irritation, nerve damage, and paralysis. 20

Particulate matter (PM2.5 and PM10)

PM2.5 and PM10 are microscopic particles that can be found in diesel or smoke, near roads, or in dusty areas.

Due to their small size, these particles can be inhaled deeply into the lungs and some can enter the bloodstream, affecting the lungs and heart. 21 Individuals with heart or lung diseases, older adults, and children are particularly at risk. Short-term exposure can worsen existing lung or heart conditions. 22 Long-term exposure is linked to chronic bronchitis and premature death in some cases. 23

Ground-level ozone (smog)

Under certain conditions, ozone can be formed when VOCs react with nitrogen oxide, which is found where combustion occurs, such as in diesel engines.